A bone marrow transplant is an often lifesaving procedure in which stem cells are removed from bone marrow, filtered, and given back either to the same person or a donation recipient. Bone marrow transplants can be used to treat or even cure certain diseases related to underproduction of stem cells or unhealthy stem cells in the body, such as aplastic anemia and leukemia.
Reasons for Bone Marrow Transplant
Bone marrow is found in larger bones in the body, such as the pelvic bones. It is the manufacturing site for stem cells, also called hematopoietic stem cells. These are pluripotential, meaning that they are the precursor cells that can evolve into the different types of blood cells, such as white blood cells, red blood cells, and platelets. If something is wrong with the bone marrow, or the production of blood cells is decreased, a person can become very ill or die.
Bone marrow transplants are typically done in patients with:
- Cancers such as leukemia, lymphoma, and multiple myeloma, in which bone marrow produces abnormal blood cells
- Bone marrow diseases like aplastic anemia, in which bone marrow stops producing blood cells needed for the body
In addition, bone marrow transplants are being evaluated for many disorders, ranging from solid tumors to other non-malignant disorders of the bone marrow, as well as for multiple sclerosis and sickle-cell disease.
Who Is Not a Good Candidate?
You may be turned down for a bone marrow transplant under the following circumstances:
- You have an uncontrolled infection.
- You have severe cardiac, vascular, kidney, liver, or lung disease.
- You suffer from disabling psychosis.
- You are over age 75.
A total of 21,696 hematopoietic cell transplantations were performed in the United States in 2016. Of these, 4,847 (22%) were unrelated transplants. One-fifth of these (20%) used bone marrow as the source.1
How Serious Is Bone Marrow Edema?
Types of Bone Marrow Transplants
There are two primary types of bone marrow transplants: autologous and allogeneic. Your healthcare provider will recommend one or the other based on the type of disease you have, as well as the health of your bone marrow, your age, and overall health. For example, if you have cancer or another disease (such as aplastic anemia) in your bone marrow, using your own stem cells is not recommended.
Autologous Bone Marrow Transplant
The Greek prefix auto- means “self.” In an autologous transplant, the donor is the person who will also receive the transplant. This procedure, also known as a rescue transplant, involves removing the stem cells from your bone marrow and freezing them. You then receive high-dose chemotherapy followed by an infusion of the thawed out frozen stem cells.
This type of transplant may be used to treat leukemias, lymphomas, or multiple myeloma.
Allogeneic Bone Marrow Transplant
The Greek prefix allo- means “different” or “other.” In an allogeneic bone marrow transplant, the donor is another person who has a genetic tissue type similar to the person needing the transplant.
Haploidentical Bone Marrow Transplant
With this type of allogeneic transplant, healthy, blood-forming cells from a half-matched donor replace the unhealthy ones. A half-matched donor is exactly what it sounds like: one who matches exactly half of your tissue traits.
Non-Myeloablative Bone Marrow Transplant
In a non-myeloablative bone marrow transplant, a.k.a. mini-bone marrow transplant, lower doses of chemotherapy are given that do not completely wipe out or “ablate” the bone marrow as in a typical bone marrow transplant. This approach may be used for someone who is older, or otherwise might not tolerate the traditional procedure.
In this case, the transplant works differently to treat the disease as well. Instead of replacing the bone marrow, the donated marrow can attack cancerous cells left in the body in a process referred to as graft versus malignancy.
Other Stem Cell Transplants
A bone marrow transplant is one of three types of stem cell transplants. In a transplant called peripheral circulating blood cell transplant (PBSC), a process called apheresis is used to remove stem cells from the blood, rather than bone marrow. Stem cells may also be obtained from cord blood banks, which store blood from a baby’s umbilical cord shortly after birth.
Recipients and Donors
Tissue types are inherited, similar to hair color or eye color, so it is more likely that you will find a suitable donor in a family member, especially a sibling.
Siblings are suitable donors 25% of the time.2
Half-matched donors usually include a person’s mother, father, or child. Parents are always a half-match for their children. Siblings have a 50% chance of being a half-match for each other.
Most people between the ages of 18 and 60 who are in good health can become a donor. If someone would like to be considered as a donor, they will have to give a blood sample and fill out a form. The National Marrow Donor Program website offers helpful information to get this process started.
Many people receive bone marrow from family members and, because of this, do not need to be considered alongside others seeking a non-related person’s donation.
If a family member does not match the recipient, or there are no related donor candidates, the National Marrow Donor Program Registry database can be searched for an unrelated individual whose tissue type is a close match.
It is more likely that a donor who comes from the same racial or ethnic group as the recipient will have the same tissue traits. Currently, whites more commonly donate marrow, hence being white yourself makes it more likely you’ll find a close match.
Those who are less likely to find a close bone marrow match will have much better luck seeking a cord blood donation; these stem cells are more “flexible,” as it were, when it comes to matching with recipients.
Your transplant team will keep you up to date on how things are proceeding with your particular match and likely wait time.
